US President Barack Obama speaks during the second presidential debate with republican presidential candidate Mitt Romney at the David Mack Center at Hofstra University in Hempstead, New York, October 16, 2012. AFP PHOTO / Saul LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)

President Barack Obama speaks during the second presidential debate with Republican presidential candidate Mitt Romney at the David Mack Center at Hofstra University in Hempstead, N.Y., on Oct. 16, 2012. (credit: SAUL LOEB/AFP/Getty Images)

HEMPSTEAD, N.Y. (CBSDC/AP) — President Barack Obama is taking responsibility for the lack of security at the U.S. diplomatic mission in Benghazi where Ambassador Christopher Stevens and three other Americans were killed during a terror attack last month.

Answering a question from an undecided voter during Tuesday night’s presidential debate, Obama says the buck stops with him when it comes to security of American personnel across the globe.

“When I say I am going to find out exactly what happened, everybody will be held accountable and I am ultimately responsible for what’s taking place there,” Obama said. “I’m always responsible.”

Obama’s comments come after Secretary of State Hillary Clinton said that she took “responsibility” for the security of Stevens and the three other Americans who died in the attack in Libya.

Romney responded to Obama saying that the White House waited too long to call it a terror attack and that the president’s policies regarding the Middle East are “unraveling before our very eyes.”

So far, the Republican challenger has not aired any television advertising on the issue, a suggestion that strategists believe it dims in importance next to the economy.

But the attack sparked one of the sharpest exchanges in last week’s vice presidential debate, when Republican vice presidential candidate Paul Ryan cited it in asserting that the administration’s foreign policy was unraveling and Vice President Joe Biden accused his rival of uttering “a bunch of malarkey.”

Biden also said that “we” had not been aware of a request for additional security at the facility, a statement that the White House later said applied to the president and vice president.